Piston machine with crankshaft



Mmhfs, 1941.

F. LJUN GSTROM 2,235,160 PISTON MACHINE WITH GRARKSHAF'J.

Filed July 16, 1938 4 Sheets-Sheet l March 1941. F. LJUNGSTRGM PISTON MACHiNE WITH CRANKSHAF' I' 4 Sheets-Sheet 2 Filed July 16, 1938 March-13, 1941- r F. 'LJuNGs-rRbM 5. 60

PISTON MACHINE WITH; CHANKSHAFT Filed July 16, 1938 4 Sheetg-Sheet 3 EX I EEEJX J57. I55 m4- }!5 I25 17 I? z ass . s-x :0 [E

' 12 I us *7 IO L\ March 18, 1941.-

PISTON MACHINE WITH CRANKSHAFT 125 m4 "155 2.1 x r F. LJUNGSTREM 2235.160

Filed July 16,- 19:58

' 4 Shets-$heet 4 Patented Mar. 18, 1941 rrs'roN l Fr Liunsstrfim, St k lm, Swed assignor to Aktiebohiget Bolinder-Munkteil, Eskilstu, Sweden, a corporation of Sweden Application July 16 1938, Serial No. 219,497

In Sweden July 21, 1937 momma. (cr es-192) My invention relates to piston machines, such as combustion motors, provided with av crank I shaft, and more particularly to piston machines which impart to= the surroundings vibrations one or a few cylinders. I 7 I Such vibrations, for instance in combustion which appear especially with motors having only r the machine.

same manner that the fly wheel equalizes the V. II

turning moment on the poweroutput shaft of This is essentially accomplished by the fact that the turning pressure reaction motors, depend to a great extent on the working 1 a I members, the machine body enclosing the piston conditions in the motor cylinders setting" up heavy continuously repeated changes oi the turn ingmoment in opposite directions due to alter-' nating gas explosions and compressions; Hence, the crankshait has aily wheel which receives the heavy impulses and delivers aneven turning impulses emanating from the piston mechanism 5 on operationv of the machine, are transferred through the machine body to the surroundings, for instance a base, byinterposition of spring mechanism. being movably join-nailed about a centercommon to the axis of rotation of the crankshaft oi the machine while the machine body is dynamically or substantially dynamically moment to the. drivenfshait.;:. The' stationary motor body is, howevengnevertheless exposed to 'balancedaround this axis, so that the machine body with respect to the said pressure reaction impulsesoscillates asa pendulum with atleast th'e'fly wheel has mink ig The' -impuls'esfin this reaction moment which'ar ,stiiimor'euneven than those which. are taken:upffbyfthejflylwheel are transierred directly through to the. surroundingaj which th 'llected to thesaid vibrations.- with combustion motors having I, I ber. Ioi. "cylinders, the "tumingf moment and-1th i corresponding reaction .turnme oment )to -themotor bed are equalized to a greatgexten ii th machine is considered as I a' mint. '1 1.1Suchf ilarg 1 motor plants with a long row of cylinders iorm. ijhowever, a yieldingly deformable member an theimpulses due'to the working conditionsii the individual cylinders are therefore still im means toeliminate the are still hishlydisturb l avoid disadvantages originatingirom the abovethe mo parted to the surroundings through the motor --bed. in order to eliminate the unfavorable influence. oi the reaction'turning momentom operation of. the motor, ithas been suggested I .to provide rubber cushions or steel springs be- 7. .tween' a combustion -motor and its' support-If D wherebyfa dampingeffected upou' the transfer foi the reaction turning-moments to thesupport. Even if thefvibrationfphenomenon .set up intther surroundings at 1; in ,this {wa re u o" ome 5 as extent, it has notbeen? possible with such simple ame, and the vibrations I a It is one object of my invention eifectiveiy to f n mentioned vibrationsjandto provide a device which practicallyentirely relieves the bed supporting the moto i and hence the surroundings fromthe impulses oithe reaction turning moments, so that the latter are converted toan substantiallyunchanged center oi gravity. The invention relates in the first place to machines .ibein'g-Tasymm'etrical with respect to the axis of rotation of the crankshaft and for instance hav inc vertical cylinder, whereby balance weights j are provided which dynamically balance the t machine around its axis of rotation. The weight :of the machine becomes by this decidedly greater,

and, the linear extension of the machine less 25.

. below thatshaft.

"In order to illustrate the inventive idea the ollowi'ng example'will be, assumed. j A one- I ylinder two-stroke motor develops 100 H. P.

Thenumbr ofjrevoiutions of the motor is I300/mih.=5 /sec. The equalized turning moment forv the grnotoris assumed to be delivered on a radialTl ev er, the length of which is 0.5 m., reckn'd i'rom the crankshait center or the motor.

'The poweracting on this lever is then 5 kg./H,

r in..all;500- kg. atabout 15 m./sec. peripheral velocity.5;The motor has a fly wheel which is assumed to have amoment of inertia correspondi ing tofa weight 101 two tons onthesame radius of 0.5 ,m.- wAslthe motor works according to the 40 two-stroke. cycle, its effect isxdel'ivred by. the

piston during-a quarter oi a revolution. The

"turning moment during this quarter accordingly. becomes 2 tonsjon 0.51m. Iradius.

assuming'that no powerv momentarily is delivered '45 It further from the motor shaft'rthe flywheeltakes up all the energy 'supplied and .is thereby accelerated. f The fly wheel whichis' equivaient to aweight of I 2 tons is 'accelerawdiby a power of likewise 2 tons, and therefore t acceleration on the assumed inertia radius;w1ll -be=the gravity, 1. e. 9.8 m./sec.,-

which is hereapproximated to 10 in. The accel-'v eration takes; place during a quarter of a revolu-.

tion, in the assumed case corresponding to a time oi 0.05 sec.1 The increase in velocity thu b ome -0.05=0.5 m./sec. Thereafter the' fly wheel delivers the en'ergyurrder a slower retardation to the shaft. The cylinder and the other parts of the motor body receive through the piston and the connectingfrod, a reacting turning moment from the crankshaft which is as great as the turning moment which was transferred to the fly wheel. Assume nowthat the motor body has the same mass of 2 tons on 0.5 m. lever as the fly wheel. The mechanical condition will be the same as above described if, on the contrary,

the fly wheel is imagined to be stationary while the motor bodyis allowed to rotate, with the mere difference that the fly wheel and the motor body have changed places.

A construction with rotating cylinder plant is often used on aero motors. The motor body will of course in this case be accelerated to the same degree as the fly wheel according to the aforesaid but in opposite direction, and v the acceleration, on a radius of inertia of 0.5 m., during a quarter of a revolution is 0.5 m./sec. The power of acceleration is of course independent of whether the fly wheel or the motorbody or both rotate, as both are subject to the same turning moment although in opposite directions. If, therefore, the fly wheel rotates with 5 revolutions/sec. and the motor body ismade free so that it can rotate about the motor shaft, it will also now be subject to an acceleration of 0.5 m./sec. during a quarter of a revolution As the time for a rotation of about a quarter of a revolution is 0.5 sec., the mean velocity and the distance performed=0.05-0.25=0.0125 m., or 12.5 mm. According to the invention a spring device is disposed between the motor body and its support, which device brings the motor body back towards the original position after each reaction impulse while delivering an even turning moment to the surroundings, whereby the motor body makes a pendulum movement with the crankshaft of the motor as the axis of rotation. Because of the fact that the motor additionally is balanced about this axis, vibrations originating from the turning reaction moments are effectively avoided.

The said spring device is preferably combined with means which automatically set the same, and thereby increase the spring power on increasing reaction turning moment and vice versa, so that the device can take up turning moments varying within broad limits without altering the position of the motor.

A further feature of the invention is to provide means for eliminating vibrations in the neighbourhood of the motor, originating from the unbalance of the reciprocating members (piston, connecting rod), of the motor. It is known to counterbalance said members by means which are heavier than the same, and which are adapted to move in paths equivalent to those of the members. In accordance with my invention themeans comprise movable eccentric disc elements journalled on eccentrics on the crankshaft, and balance weights Journalled on said elements, whereby means are provided for guiding said weights.

Further and more detailed objects of the invention, together with the manner in which they and the above stated objects are attained, may best be understood from a consideration of the following description of the invention as embodied in suitable forms of machines, taken in conjunction with the accompanying drawings, forming a part of this specification, of which:

2,235,160 I a Fig. I shows a longitudinalv section through a one-cylinder internal combustion motorhcon structed accordingto the invention.

Fig. II shows the motor viewedin the direction of the shaft. partly in section on the llneiII-QII Orr-fer.

Fig. III shows adiagram illustrating the work I ing manner of the motor.'-

Fig. VI shows 'the same element partly inan axial section. l a Figs. VII and VIII show side elevations of details pertaining to the same embodiment.

Fig. IX shows another embodiment of means for balancing the movable members of a machine viewed in a vertical section in the plane of. the crankshaft on the line IX-IX of Fig. K.

Fig. X shows a section on the line X-e-X of Fig. IX.

Figs. XI and X11 illustrate diagrammatically the machine according to this embodiment and adetail thereof, respectively.

Fig. XIII shows a portion of a piston machine embodiment of the int:

according to a further vention.

In the drawings, in designatesthe crank case. of the motor and II its cylinder in which works in known manner a piston l2. Pistoni l2--is'con- I nected by a connectingrod "to the-crank ll of a crankshaft l5, which latter carriesa fly wheel 65. The crankshaft ills journalied in bearings it, which are rlgidly'flxed to"themotor body l0. MOtOI' body "I is rotatably joumalled in the base or frame I 8 by the fact that the bearings ii are provided with sliding surfaces, against.

bearings l1 rigidly secured to the base. The centers of these sliding surfaces are concentric with the axis of rotation 2! of the'crankshaft.

Below the shaft the crank case is,formed as a balance weight 20 (Fig. II), which statically and dynamically balances the motor body which is pivotable in the frame bearings I! about the axis of the crankshaft. The weight of the motor aggregate becomes in this way greater below than above the crankshaft. The linear extension of the motor is nevertheless smaller in the lower part. The motor is preferably symmetrical on each side of the symmetry plane IIII (Fig. I), in which all the forces on the piston, the connect ing rod and the crankshaft are active.

The reaction turning moment on the motor on its operation is transferred to the stationary base is through a spring device, which in the embodiment according to Figs. I--IV consists in one or several springs 22, connected to a lever 21,

rigidly secured on the crank case it. Below the spring 22 a piston 24 is arranged which moves in a cylinder 25 which, through a conduit 26, is in servo-motor-cylinder 21 is connected an oil con-' duit 36 which is provided with a check valve 31. An oil discharge channel 38 extends from the cylinder 2? at a distance above its bottom.

lines 42 and 2| in Fig. I. The stroke length of Laterally 'of'the elements l connecting the crank pin ll with the crankshaft l5, and which in known manner may be round and concentric :withthe axis of the shaft, the crankshaft'is provided with preferably forged eccentrics 4|, the eccentricity of which is indicated by'the center the eccentrics sl'is, in the embodiment accordpreferably is connected through a conduit 50 to a silencer 5|, as appears from Fig. I. The pipe 50 may be provided with spherical surfaces'engaging flange 52 and a flange of the silencer 5i.

Packing rings 53 may be disposed in said surfaces. By this device the cylinder ll may oscillate relatively to the stationary silencer 5|, without jeopardizing the proper sealing at the gas exhaust.

The mode of operation is as follows: The pulsatingreactions acting on the motor body l0, H, with its balance weight 20 are, during normal operation of the motor, transferred through the lever 23 and the spring member 22 to the stationary frame 88. The motor body thereby acts as an oscillating fly wheel, while the spring 22 transfers an equalized reaction turn- 1 ing moment to the surroundings; The spring is automatically set against the lever- 23 by the servo-motor cooperating with the spring, dependent on the size of the reaction impulses on the motor housing Hi, .[If the lever 23 is iturned downwardly in Fig. II under the action of a heavy reaction impulse, the slide valve 28- will in a certain positionopen connection with the conduit 83 for pressure 011, hich flows into the cylinder chamber 25 below the piston 24, resulting in a compression and setting of the spring 22. In a certain upper .position of the slide valve 28 its channel '32 on the contrary, communicates with the discharge conduit 84, and oil can now flow out from the cylinder chamber below the piston 25. By this device the movability of the motor around the crankshaft is kept withina very limited range, at the same time as the turning moment is transferred to the motor bed by a sensitive spring with great setting length. This setting lengthor the piston stroke of the cylinder 25 is in accordance with the invention so determined that it is several times, for instance ten times, greater than the oscillation amplitude of the motor body III, II. As stated above this oscillation amplitude may be kept within utmost reasonable limits and may thus on 0.5 in. radius be restricted to somewhat over one cm.

If the compression length of the spring is for instance ten times the swinging amplitude of the motor, the turning moment transferred to the surroundings varies with one tenth of the mean turning moment. If this mean turning moment is as in the above example one fourth of the maximum turning moment during the explosion period (in reality the diiference is much greater), the reactive impulses transferred to the surroundings in a motor of conventional type will be deassume creased to one tenth of the mean turning moment,

that is to 2.5% of the maximum value otherwise common. This means also that the shakings of the surroundings originating from the turning impulses of the motor, are decreased to a value which merely is some per cent of the common one.

From the diagram shown in Fig. III for the oscillation movements occurring during normal operation of the motor, it appears that rapid and heavy retardations and accelerations B5 and 56 respectively, are set up at the explosion during the crank stroke alternating with the relatively weaker returning forces 51 from the spring 22. The amplitude 58 gets the above mentioned size whereby, however, the continuous working condition diifers from that described above, inasmuch as the motor body is, H, with its balance weight 20 during the explosion in the cylinder is first retarded to stationary position, and is thereafter accelerated in opposite direction. The time of 0.05 see, above assumed is thus subdivided into halves, the one characterized by retardation and the other one by acceleration. These two periods of movement take place during a fourth of a whole stroke, while the remaining three fourths are characterized by a retardation and an acceleration, with a return force dependent on the setting of the spring 22. Assuming that this force is one fourth of the force set up in the cylinder during the explosion, this part of the swinging amplitude will be four times as long as the other one, and corresponds to the portion of the diagram positioned below the line 59 in Fig. III.

The final result is thus in all events an amplitude which has a value of between one and two cm. in the above example.

Upon starting of the motor there is another condition acting than during normal operation,

since the piston, when started from rest, is under the influence of the first explosion during a period several times longer than is the case when the motor works at full speed. This means thatthe fly wheel and the motor body are accelerated in opposite directions during the influence of an impulse of much longer duration than normal.

The oscillation path or the amplitude would therefore, if allowed to be freely developed, increase to values which would be practically inconceivable. The slide valve 28 connected to the lever 23 is for this reason preferably formed as a dash pot or buifer piston which enlarge oscillating movement of the motor passes the outlet opening 38 of the cylinder 21, whereby oil confined-in this cylinder below the opening 38 takes up the excess of turning moment of the motor.

In case the motor is to be constructed for reverse as well as for forward operation, driving a further spring device of similar kind may be provided on the opposite side of the motor shaft.

Fig. IV serves merely to illustrate the working manner of a device balancing the inner movable motor members. The piston is, as in the foregoing, designated by I2, and the connecting rod by i3. The counterweight 44 working between vertical guide members, is arranged diametrically opposite the piston l2, and cooperates with the same crankshaft as the piston by means of a connecting rod or lever 43, which in Fig. IV is half as long as the connecting rod I 8. The stroke of the eccentric lever 43, is also half as long as that of the connecting rod 83. The counterweight do is in this case twice the weight of the piston 42 and, moreover, the weight of the arm d3 is twice that of the connecting rod 03.

The piston mechanism is obviously from dynamic point of view characterised by two reciprocating uniform movements; one of which has half the dimension of the other but works with double the weight. The balance is proper, as the center of gravity of the system always coincides with the axis of rotation.

In Figs. V-VIII an embodiment of a balance device for the piston mechanism according to the invention is shown. which permits a several times greater decrease of eccentricity or stroke length 01 the balancing masses. l2 again designates the piston, and It the connecting rod which, at one end, is journalled on the crank pin ll of the crankshaft l5. For better understanding of this embodiment an imaginary eccentric arm 60 is illustrated in Fig. V, which at one end is joumalled in the eccentric 8i diametrically opposite to the crank pin l4, and in its other end carries a balance weight-G2. It is evident that the balancing elements Bil, 6|, 2, would operate in the manner aimed at according to the invention, even with such a small eccentricity in relation to the crank journal II as for instance 1:7. if they had a u weight which were in inverse proportion as many n outer circular circumference of which has. the same center asthe journal SI of the eccentric 1 lever SI, for the imagined counter-weight S2.- The times greater than that of the piston members I2,

II, This is accomplished according to the invention by the iact that the imagined eccentric I in reality corresponds to a larger eccentric Bla, but with the same center as the imagined one and moreover that the real eccentric Ila carries an eccentric lever or disc like member "a, the

real eccentric disc to carries in the same manner as the imagined one the balance weight 2a; which surrounds the cylindrical outer surface or the eccentric disc "a, and which is movable vertically between guides 03. The whole unit considered as a single mass was a square disc, has

obviously a common center of gravity which by movement from the eccentric "a is made to move up and down under the geometrically determined acceleration conditions which are illustratedby' the action of the imaginary eccentric rod to on the counter-weight 82. Also in this case the'piston l2 gets an ideally proper counter-balance by the movement of the eccentric Gla, the eccentric disc 60a, and of the balance weight 620. As appears from Fig. VI, the counter-weights on each side of the crank journal I4 maybe provided with additional weights 64, for instance placed below the balance weights 62a. Y

The members balancing the piston mechanism produce vertical acceleration and retardation forces symmetric with the forces which act on the piston I2, and on the connecting rod I3, which latter however, may be said to correspond to a weightless imaginary eccentric lever 80. The movable counter-balancing members are therefore to be adapted also to balance those parts of the connecting rod, which more or less have an acceleration course characterized by the movements of the piston. 1

In the embodiment according to Figs. rx-xn, the same reference characters designate equivalent parts as in the foregoingembodiments. The crankshaft I5 is provided with two cylindrical eccentrics I22, the center lines I 24 oi which are eccentrically displaced relatively to the axis of rotation H of the crankshaft on the diametrically opposed side of the shaft I I4. Around the cylindrical eccentrics I23 are provided two eccentric sleeves I25, which with their outer surface preierably being cylindrical are iournalled in the crank case Ill; and the center lines I2 of which are positioned in" a plane through the axis of ro-' tation 2| of the crankshaft, and through the center line I21 of the piston pin I ll of the connectins rod I3. The eccentricity of the sleeves I25 is so chosen that the distance I28 (Fig. XII) between their axis I26 and the axis 12! of the eccentrics I23, is as many or substantially as many times smaller than the distance between theaxis III and I21, as the distance between the axis I24 and 2i is smaller than the distance between the axis H4 and H. In this way the motor case and the eccentric sleeves I2! move in the same manner as the element I2. I3, although on adecreased scale. The movement-of the motor case and the sleeves I25, is diametrically opposed tothe movement of the piston I2 and the connecting rod I3.

respectively. The inventive idea may be illustrated in such way that a connecting rod I30 of though with' a stroke length only corresponding to, 1 I 7 .double the distance between the respective axes oi rotation2l, I2l,. oi thecrankshait II and the eccentrics I23." The other'bearing center I240! p '7 the imaginedcoimectlnl r diiilns moved in a," circular path around :the jafls f'of rotation 2Ijfof the .crankshait;i-'correspouding to -thei rotational J movem ntwhic iszcsrrieapuaby the crank It and its axis smii w-a t m +1 Fmm t li om 'aii is evident that f the geometrical paths'o'fythe eccentric sleeves l2l;1:

whichhave the same tunction asthe connecting;

rod l3, and of the, motor "case. are eduivalentto the paths of theconnectingrod; "and the il -y ton l2, merely with the diiierence that theiirst mentioned paths are diametrically opposed to the last mentioned, and moreover to'a great extent decreased.

I32, which. balance the crank about the axis 01 rotation 2|. The balance obtained by oms iournalling the motor case II,II, is therefore j. equivalent to a straight-lineup-and-down moves,

mentor the motor case The motor case is m: I

this embodiment guided byv two bars m mes.

" In the embodiment according to Figs. 1 I the crank I4 is provided. with counter-weights" vertical. up and-"down movementot the motor case'is arcuate; Thus the movement does not 60 -ever, as;itsfainplitude is verysmall, the actual path of movement, will difler merely by a few degrees from a straight line, which is without prac- I tical importance. The bars may of course'be rejplaced by guides or the like, provided for in- 'j sce ex tly along 'a'jtraight line. How

stance 'on thefrigid bearing housings H, which give an exactstraight-line movement.

.Ifia piston machine ffor instance of the one: cylinder type, is imagined to float freely in the air-with its various members, such as piston, con- Ynectlngrod; etc.-, working in normal manner, any reaction forces can obviously not be transferred .to-the foundation or surroundings due to the ab sence 0! contact with the same. *As the machine is not-influenced, by outer forces, its center of gravity can therefore not be moved. If the piston for instance is moved up and down, the other parts of the machine will obviously move in a similar manner although in opposite direction.

motor members, the amplitude of the movements of the machine and the piston will be in inverse proportion to the weight or mass of the bodies.

the above example make an up: and-down movement with 4 mm. amplitude.

In accordance'with my invention means are provided ensuring an ideal balancing in accordaforesaid, i. e. so that outwardly acting forces are not set up. The unbalances ocmotor, for instance by the movement of the piston, are balanced by the motor case proper, brought to make a diminutive movement of the same kind and in a path fully determined. The relations between the movements of the inner elements and of the motor are so chosen, that they are in inverse proportion to the masses of the respective parts. The center of gravity of the machine as a unit always has a constant or substantially constant position which coincides with the axis of rotation of the power output shaft of the machine. In accordance with the invention, the motor does not shake the motor bed, but vibrates only itself at the same time as the advantage of a rigidly journalled crankshaft is en sured according to the invention.

' The movable motor case may in the embodiment according to Figs. IX-XII be prevented from rotating relatively to the surroundings by means of a spring member cated in Fig. XI. The motor may of course be provided with means for taking up and equalizing the uneven turning moments,such as described in connection with Figs. I-III.

Fig. XIII shows an balance weights I32 for the crank are omitted, so that the center of gravity of the crank is spaced from the axis of shaft. Also in this case a balancing by means of the motor casing may be accomplished in accordance with the invention. In Fig. XIII, I23 designates the eccentrics of the crankshaft IS, the axis of rotation I24 of which lies at a distance from the axis of rotation 2| in the same manner as above described, i. e. this distance is in relation to the distance between the axes Ill and 2I, as is the distance'between the axis I26 of the eccentric sleeves I25 and the axis I24 to the distance between the axis Ill and I21 according to Fig. IX. The axis 2I was in other words the. axis of the crankshaft in the foregoin g embodiment. The bars I33 are in Fig. XIII concentrically journalled relatively to the axis 2i. The axis H is, however, in turn displaced relative to the axis I 31 of the crankshaft I 5, so that the distance between the axis 2| and I31 is in relation to the distance between the axis II I of the crank and the axis'I31, as the relation between the masses of the motor case and of the crank. The axis of rotation ll of the bars I33 in the embodiment according to Fig. m1, being eccentric to the axis of rotation I31 of the crankshaft I5, is positioned hr 2. plane through the axis I31 and lid. The axis 2i is positioned on the side opposite the axis I31, relative to the axis lid of the crank. As the. bars I33 are eccentricaily journalied, the center of gravity of by the fact that it positively is,

I36 diagrammatically .indiembodiment in which the 7' be journalied in needle bearings.

rotation 2I of the crank the motor rotates around the axis of rotation I31 of the crankshaft, and copies on a decreased scale the movement of the crank II4. A full balance is achieved, or in other words the center of gravity of the motor as a unit will maintain a constant position coinciding with the axis I31 of the crankshaft, in spite of the unbalance of the crank. .The rotational movement of the center of gravity of the motor case is combined with its up-and-down reciprocating movement to an oval path. The amplitude of the combined movement in up-and-down direction is somewhat greater than at the embodiment according to Fig. IX-XII. v

The invention is applicable to all kinds of single or multi-cylinder machines with vertical cylinders. Moreover, the invention may be applied to compressors and other kinds of piston machines having vibrations. Multi-cylinder machines are suitably provided with separate spring means for each cylinder, which are built independent of each other. The advantages gained by the invention are especially noticeable at slowrotating, for instance one-cylinder'machines, for driving vessels such as fishing boats, or the like. According to my invention a strong and simple machine may be utilized without being forced to take into account irritating shaking of the hull of the vessel. The pressure oil required for the operation of the servo-motor in the embodiment according to Fig. I, may be taken from the oil circulation system of the motor. The eccentric disc 60a according to Figs. V-VIII, may be provided with an external bearing surface against the weight 62a, only extending through part of the circumference, that is to say a portion (a segment) of the disc at the lower end thereof in Fig. V. may be cut away. The inner bore of the frame .620; is in such case provided with a sliding or bearing surface in the form of an arc which does not enclose the whole disc 60a;

The excenter sleeves I25 in the embodiment according to Figs; IX-XII, may on the outer face The invention does not exclude supporting the whole motor aggregate on a soft resilient base, for instance in order to avoid noise vibrations. In this case the bearing housings I1 or the base supporting the same, may be mounted on a resilient support. In Figs. IX-XIII two different positive movements are shown, which eliminate the shaking action of'the movable motor members on the surroundings. These positive movements are caused directly by the "crankshaft.

able, and moreover the movements may be caused in other manner, for instance by means of cam members which positively act on the motor case.

From the foregoing description it will be apparent that numerous changes and modifications may be made within the scope of the invention, which Is to be considered as embracing'all forms of apparatus falling within the scope of the appended claims.

' 1. In a device'bf the class described,- a body structure, a piston reciprocable within said body,

a crankshaft, said'body being turnable with re- A' greater number of other movements is, however, conceivspect to said crankshaft in a plane normal to the axis of rotation of said shaft, supporting structure for turnably supporting said body-about said crankshaft, said body being substantially dynamically balanced about its turning axis, and means for resiliently resisting turning of said body with respect to said supporting structure,

said means providing increasing resistance upon increasing turning of said body from a normal position.

2. In a device of the class described, a body structure, a crankshaft rotatably mounted in said body, -a piston connected to said crankshaft and reeiprocable within said body, supporting structure, said body being turnably mounted with respect to said supporting structure about an axis concentric with the axis of rotation of said crankshaft, said body being substantially dynamically balanced about said axis, and means for resiliently resisting turning of said body with respect to said supporting structure, said means providing increasing resistance upon increasing turning of said body from a normal position.

3. In a device of the class described, a body structure including a cylinder, a piston reciprocable within said cylinder, a crankshaft rotatable with respect to said body, supporting structure for turnably supporting said body in a plane normal to the axis of rotation of said crankshaft, said body being substantially dynamically balanced-about its turning axis', the weight of that portion of said body on the side of said crankshaft occupied by said cylinder being substan tially less than the weight of the portion on the opposite side, and means for resiliently resisting turning of said body with respect to said sup,- porting structure, said means providing increasing resistanceupon increasing turning of said body from a normal position.

4. In a device of the class described, a body structure including a cylinder, a piston reciprocable within said cylinder, a crankshaft rotatable with respect to said body, supporting structure for turnably supporting said body in a plane normal to the axis of rotation of said crankshaft, said body being substantially dynamically balanced about its turning axis, resilient means for resisting turning of said body with respect to said supporting structure, and means for varying the resistance to turning offered by said resilient means, so as to increase the resistance the further said body turns from a normal position.

5. In a device oi. the class described, a body structure including a cylinder, 8. piston reciprocable within said cylinder, a crankshaft rotatable with respect to said body, supporting structure for turnably supporting said body in a plane normal to the axis of rotation of said crankshaft, said body being substantially dynamically balanced about its turning axis, resilient means for resisting turning of said body with respect to said supporting structure, and means responsive to increasing tendency of said body to turn for increasing the resistance to turning offered by said resilient means.

6. In a device of the class described, a body structure including a cylinder, a piston reciprocable within said. cylinder, a crankshaft rotatable with respect to said body, supporting structure for turnably supporting said body in a plane normal to the axis of rotation of said crankshaft, said body being substantially dynamically balanced about its turning axis, a movable abutment, spring means disposed between'said body and said abutment for limiting turning of the body with respect to said supporting structure, and means responsive to an increase in the turning amplitude of said body for moving said abutment in a direction to increase the resistance to turning offered by said spring means.

7. Ina device of the class described, a body structure including a cylinder, 9, piston reciprocable within said cylinder, a crankshaft rotatable with respect to said body, supporting structure for turnably supporting said body in a plane normal to the axis of rotation of said crankshaft, said body being substantially dynamically balanced about its turning axis, a movable abutment, spring means disposed between said body and said abutment for limiting turning of the body with respect to said supporting structure, and means responsive toan' increasein the turnmg amplitude of said body for moving said abutment a distance substantially greater than said increase in amplitude and in a direction to increase the resistance to turning offered by said spring means.

8. In a device of the class described, a body structure including a cylinder, a piston reciprocable within said cylinder, a. crankshaft rotatable with respect to said body, supporting structure for turnably supporting said body in a plane normal to the axis of rotation of said crankshaft, said body being substantially dynamically balanced about its turning axis, a piston abutment, spring means between said body and abutment for limiting turning of the body with respect to said supporting structure, means for applying fluid pressure to said piston abutment, a valve for controlling said fluid pressure, and

means for adjusting said valve in response to variations in the turning amplitude of said body so that an increase in said amplitude results in ment for limiting turning of the body with respect to said supporting structure, means for.

applying fluid pressure to'said piston abutment, a

valve for controlling said fluid pressure, means for adjusting said valve in response to variations in the turning amplitude of said body so that an increase in said amplitude results in an increase in the fluid pressure, and liquid bufler means for positively limiting said amplitude.

10. In a device of the class described, a body structure including a cylinder, 9. piston reciprocable within said cylinder, a crankshaft rotatable with respect to said body, supporting structure for turnably supporting said body in a plane normal to the axis of rotation of said crankshaft, said body being substantially dynamically balanced about its turning axis, a piston abutment, spring means between said body and abutment for limiting turning of the body with respect to said supporting structure, means for applying fluid pressure to said piston abutment, a slide valve for controlling said fluid pressure. means connecting said valve to said body so that the valve is moved by turning of the body, the valve being arranged to increase the pressure upon an increase in the turning amplitude of the body, and means associated with said valve providing a liquid bufler for positively limiting movement of said valve and the turning amplitude of said body connected thereto.

11. In a device of the class described, a body structure including a cylinder, a piston reciprocable within said cylinder, 9. crankshaft rotatable with respect to said body, supporting .mounted on said eccentric structure for turncbly supporting said body in s. plane normal to the axis of rotation of said crankshaft-an eccentric rotatable with said crankshaft, a member eccentrically jam-nailed on said eccentric, and a balancing weight rotatably mounted on said member and reciprccably guided with respect to said body.

12. In a, device of the class described. a supporting structure, a dynamically balanced crankmeans for limiting turning of said body tire with respect to said supporting structure.

13. In a. device or the class described, e to tatable crankshaft having an eccentrically hated crank pin, a reciprocable piston, it connect for connecting said piston to we on said can 180' to said crank pin. a

flrcd' acid pin, aneccenmember eccentrically iournailed on said eccentric, s balance weight journalled on said. the movement at said the path of travel of member,

weight in a. path parallel to said recible piston.

out oi phase with respect is. In a, device at the class described, s. ro-

tstsble crankshaft 4s; reciprocable piston, e connecting rod for connecting said piston to said pin, an

c on said shsit 180 out of phase with re- 7 iournalied on iournslied on crank pin, s member eccentrically said eccentric, a. balance weight said member. the rsmus of curvatureoi the journal between said member and said bgal weisht having an eccentricelly lo-' 

